Molecules can only exist in the atmospheres of very cool stars or in the cooler regions of stars higher in the main sequence, such as in sunspots in our own sun. Most of the observed species are diatomics and are often transitory. Brown dwarfs, on the other hand, can be cool enough to support complex molecules such as methane. Two spectral classes, L (~1300 to ~2000 K) and T (below ~1300 K), have been created for them.

NOTE: Molecule identifications in the table below are intended to be representative, not exhaustive. As with any identification, certainties will vary; a molecule in italic font is a tentative detection. Sources indicate that about 25 species have been identified in the Sun.

See also: The Classification of Stellar Spectra (an informative discussion on star type) and the Wikipedia article on spectral classes.


OBJECT/TYPE MOLECULES
(click for citations)
GENERAL CITATION
Sun ("Sol")
(G2V star)
AlF AlH CaH CH
CH+ CN CO CrH
CuH H2 H2O HCl
NH OH ScO SH
SiH TiH TiO ZrO
On Molecules in Sunspots
H. Wöhl, Solar Phys 16, 362-272 (1971)
R Andromedae
(S star)
CeO SH
Über helle Linien im Spectrum von R Andromedae
T. E. Espin, Astronomische Nachrichten 123, 31 (1890)
IRAS 12311-3509
(N star)
SiC2
IRAS 12311-3509: A Carbon Star with SiC2 Emission
T. Lloyd Evans, M. E. Hurst, and P. J. Sarre, MNRAS 319, 111-120 (2000)
Mira (ο Ceti)
(S star)
TiO VO
Maxima of ο Ceti and Other Variables
R. O'Halloran, Pub Astron Soc Pac 11, 246 (1899)
GD 165B
(L brown dwarf)
CrH FeH
The Unique Spectrum of the Brown Dwarf Candidate GD 165B and Comparison to the Spectra of Other Low-Luminosity Objects
J. D. Kirkpatrick, T. J. Henry, and J. Liebert, ApJ 406, 701-707 (1993)
ε Indi Ba
(T brown dwarf)
CH4 H2O CO
ε Indi B: A New Benchmark T Dwarf
R. D. Scholz, M. J. McCaughrean, N. Lodieu, and B. Kuhlbrodt, A&A 398, L29-L33 (2003)
Gliese 229B
(T brown dwarf)
CH4 H2O CO
Discovery of a Cool Brown Dwarf
T. Nakajima, B. R. Oppenheimer, S. R. Kulkarni, D. A. Golimowski, K. Matthews, and S. T. Durrance, Nature 378, 463-465 (1995)
Gliese 570D
(T7.5 brown dwarf)
CH4 H2O NH3
Discovery of a Brown Dwarf Companion to Gliese 570ABC: A 2MASS T Dwarf Significantly Cooler than Gliese 229B
A. J. Burgasser, J. D. Kirkpatrick, R. M. Cutri, H. McCallon, G. Kopan, J. E. Gizis, J. Liebert, I. N. Reid, M. E. Brown, D. G. Monet, C. C. Dahn, C. A. Beichman, and M. F. Skrutskie, ApJ 531, L57-L60 (2000)
VY Canis Majoris
(M star, red hypergiant)
AlO ScO TiO VO
Cataloged by Lalande 7 March 1801.


Maintained by DE Woon
Updated 22 January 2013